10 files changed, 291 insertions, 50 deletions

diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index ae18f12480b1..93abd69739e4 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -427,12 +427,13 @@ proc0_init(void *dummy __unused)
 	td->td_priority = PVM;
 	td->td_base_pri = PUSER;
 	td->td_oncpu = 0;
-	td->td_flags = TDF_INMEM;
+	td->td_flags = TDF_INMEM|TDP_KTHREAD;
 	p->p_peers = 0;
 	p->p_leader = p;
 
 
-	bcopy("swapper", p->p_comm, sizeof ("swapper"));
+	strncpy(p->p_comm, "kernel", sizeof (p->p_comm));
+	strncpy(td->td_name, "swapper", sizeof (td->td_name));
 
 	callout_init(&p->p_itcallout, CALLOUT_MPSAFE);
 	callout_init_mtx(&p->p_limco, &p->p_mtx, 0);
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index 94b949b33ccf..af038a23ee92 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -136,8 +136,7 @@ exit1(struct thread *td, int rv)
 	 * MUST abort all other threads before proceeding past here.
 	 */
 	PROC_LOCK(p);
-	if (p->p_flag & P_HADTHREADS) {
-retry:
+	while (p->p_flag & P_HADTHREADS) {
 		/*
 		 * First check if some other thread got here before us..
 		 * if so, act apropriatly, (exit or suspend);
@@ -161,8 +160,8 @@ retry:
 		 * re-check all suspension request, the thread should
 		 * either be suspended there or exit.
 		 */
-		if (thread_single(SINGLE_EXIT))
-			goto retry;
+		if (! thread_single(SINGLE_EXIT))
+			break;
 
 		/*
 		 * All other activity in this process is now stopped.
diff --git a/sys/kern/kern_idle.c b/sys/kern/kern_idle.c
index 43ce37a2faee..c875e8592a43 100644
--- a/sys/kern/kern_idle.c
+++ b/sys/kern/kern_idle.c
@@ -60,27 +60,25 @@ idle_setup(void *dummy)
 
 #ifdef SMP
 	SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
-		error = kproc_create(sched_idletd, NULL, &p,
-		    RFSTOPPED | RFHIGHPID, 0, "idle: cpu%d", pc->pc_cpuid);
-		pc->pc_idlethread = FIRST_THREAD_IN_PROC(p);
+#endif
+		error = kproc_kthread_add(sched_idletd, NULL, &p, &td,
+		    RFSTOPPED | RFHIGHPID, 0, "idled", "idle: cpu%d", pc->pc_cpuid);
+#ifdef SMP
+		pc->pc_idlethread = td;
 #else
-		error = kproc_create(sched_idletd, NULL, &p,
-		    RFSTOPPED | RFHIGHPID, 0, "idle");
-		PCPU_SET(idlethread, FIRST_THREAD_IN_PROC(p));
+		PCPU_SET(idlethread, td);
 #endif
+		p = td->td_proc;
 		if (error)
 			panic("idle_setup: kproc_create error %d\n", error);
 
-		PROC_LOCK(p);
 		p->p_flag |= P_NOLOAD;
-		td = FIRST_THREAD_IN_PROC(p);
 		thread_lock(td);
 		TD_SET_CAN_RUN(td);
 		td->td_flags |= TDF_IDLETD;
 		sched_class(td, PRI_IDLE);
 		sched_prio(td, PRI_MAX_IDLE);
 		thread_unlock(td);
-		PROC_UNLOCK(p);
 #ifdef SMP
 	}
 #endif
diff --git a/sys/kern/kern_intr.c b/sys/kern/kern_intr.c
index ae749766561f..4d450f462351 100644
--- a/sys/kern/kern_intr.c
+++ b/sys/kern/kern_intr.c
@@ -80,6 +80,7 @@ struct	intr_event *clk_intr_event;
 struct	intr_event *tty_intr_event;
 void	*softclock_ih;
 void	*vm_ih;
+struct proc *intrproc;
 
 static MALLOC_DEFINE(M_ITHREAD, "ithread", "Interrupt Threads");
 
@@ -171,8 +172,7 @@ ithread_update(struct intr_thread *ithd)
 		pri = TAILQ_FIRST(&ie->ie_handlers)->ih_pri;
 
 	/* Update name and priority. */
-	strlcpy(td->td_proc->p_comm, ie->ie_fullname,
-	    sizeof(td->td_proc->p_comm));
+	strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name));
 	thread_lock(td);
 	sched_prio(td, pri);
 	thread_unlock(td);
@@ -332,16 +332,15 @@ ithread_create(const char *name)
 {
 	struct intr_thread *ithd;
 	struct thread *td;
-	struct proc *p;
 	int error;
 
 	ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
 
-	error = kproc_create(ithread_loop, ithd, &p, RFSTOPPED | RFHIGHPID,
-	    0, "%s", name);
+	error = kproc_kthread_add(ithread_loop, ithd, &intrproc,
+		    &td, RFSTOPPED | RFHIGHPID,
+	    	    0, "interd", "%s", name);
 	if (error)
 		panic("kproc_create() failed with %d", error);
-	td = FIRST_THREAD_IN_PROC(p);	/* XXXKSE */
 	thread_lock(td);
 	sched_class(td, PRI_ITHD);
 	TD_SET_IWAIT(td);
@@ -357,16 +356,15 @@ ithread_create(const char *name, struct intr_handler *ih)
 {
 	struct intr_thread *ithd;
 	struct thread *td;
-	struct proc *p;
 	int error;
 
 	ithd = malloc(sizeof(struct intr_thread), M_ITHREAD, M_WAITOK | M_ZERO);
 
-	error = kproc_create(ithread_loop, ih, &p, RFSTOPPED | RFHIGHPID,
-	    0, "%s", name);
+	error = kproc_kthread_create(ithread_loop, ih, &intrproc,
+		    &td, RFSTOPPED | RFHIGHPID,
+	    	    0, "interd", "%s", name);
 	if (error)
 		panic("kproc_create() failed with %d", error);
-	td = FIRST_THREAD_IN_PROC(p);	/* XXXKSE */
 	thread_lock(td);
 	sched_class(td, PRI_ITHD);
 	TD_SET_IWAIT(td);
@@ -688,7 +686,7 @@ intr_event_schedule_thread(struct intr_event *ie)
 	 */
 	if (harvest.interrupt && ie->ie_flags & IE_ENTROPY) {
 		CTR3(KTR_INTR, "%s: pid %d (%s) gathering entropy", __func__,
-		    p->p_pid, p->p_comm);
+		    p->p_pid, td->td_name);
 		entropy.event = (uintptr_t)ie;
 		entropy.td = ctd;
 		random_harvest(&entropy, sizeof(entropy), 2, 0,
@@ -706,12 +704,12 @@ intr_event_schedule_thread(struct intr_event *ie)
 	thread_lock(td);
 	if (TD_AWAITING_INTR(td)) {
 		CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid,
-		    p->p_comm);
+		    td->td_name);
 		TD_CLR_IWAIT(td);
 		sched_add(td, SRQ_INTR);
 	} else {
 		CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
-		    __func__, p->p_pid, p->p_comm, it->it_need, td->td_state);
+		    __func__, p->p_pid, td->td_name, it->it_need, td->td_state);
 	}
 	thread_unlock(td);
 
@@ -842,7 +840,7 @@ intr_event_schedule_thread(struct intr_event *ie, struct intr_thread *it)
 	 */
 	if (harvest.interrupt && ie->ie_flags & IE_ENTROPY) {
 		CTR3(KTR_INTR, "%s: pid %d (%s) gathering entropy", __func__,
-		    p->p_pid, p->p_comm);
+		    p->p_pid, td->td_name);
 		entropy.event = (uintptr_t)ie;
 		entropy.td = ctd;
 		random_harvest(&entropy, sizeof(entropy), 2, 0,
@@ -860,12 +858,12 @@ intr_event_schedule_thread(struct intr_event *ie, struct intr_thread *it)
 	thread_lock(td);
 	if (TD_AWAITING_INTR(td)) {
 		CTR3(KTR_INTR, "%s: schedule pid %d (%s)", __func__, p->p_pid,
-		    p->p_comm);
+		    th->th_name);
 		TD_CLR_IWAIT(td);
 		sched_add(td, SRQ_INTR);
 	} else {
 		CTR5(KTR_INTR, "%s: pid %d (%s): it_need %d, state %d",
-		    __func__, p->p_pid, p->p_comm, it->it_need, td->td_state);
+		    __func__, p->p_pid, td->td_name, it->it_need, td->td_state);
 	}
 	thread_unlock(td);
 
@@ -1100,9 +1098,9 @@ ithread_loop(void *arg)
 		 */
 		if (ithd->it_flags & IT_DEAD) {
 			CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
-			    p->p_pid, p->p_comm);
+			    p->p_pid, td->td_name);
 			free(ithd, M_ITHREAD);
-			kproc_exit(0);
+			kthread_exit(0);
 		}
 
 		/*
@@ -1171,9 +1169,9 @@ ithread_loop(void *arg)
 		 */
 		if (ithd->it_flags & IT_DEAD) {
 			CTR3(KTR_INTR, "%s: pid %d (%s) exiting", __func__,
-			    p->p_pid, p->p_comm);
+			    p->p_pid, td->td_name);
 			free(ithd, M_ITHREAD);
-			kproc_exit(0);
+			kthread_exit(0);
 		}
 
 		/*
diff --git a/sys/kern/kern_kthread.c b/sys/kern/kern_kthread.c
index a9359359dabd..aff0fe6a1c37 100644
--- a/sys/kern/kern_kthread.c
+++ b/sys/kern/kern_kthread.c
@@ -39,6 +39,8 @@ __FBSDID("$FreeBSD$");
 #include <sys/unistd.h>
 #include <sys/wait.h>
 #include <sys/sched.h>
+#include <vm/vm.h>
+#include <vm/vm_extern.h>
 
 #include <machine/stdarg.h>
 
@@ -95,7 +97,9 @@ kproc_create(void (*func)(void *), void *arg,
 
 	/* this is a non-swapped system process */
 	PROC_LOCK(p2);
+	td = FIRST_THREAD_IN_PROC(p2);
 	p2->p_flag |= P_SYSTEM | P_KTHREAD;
+	td->td_pflags |= TDP_KTHREAD;
 	mtx_lock(&p2->p_sigacts->ps_mtx);
 	p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
 	mtx_unlock(&p2->p_sigacts->ps_mtx);
@@ -105,9 +109,12 @@ kproc_create(void (*func)(void *), void *arg,
 	va_start(ap, fmt);
 	vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
 	va_end(ap);
+	/* set up arg0 for 'ps', et al */
+	va_start(ap, fmt);
+	vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
+	va_end(ap);
 
 	/* call the processes' main()... */
-	td = FIRST_THREAD_IN_PROC(p2);
 	cpu_set_fork_handler(td, func, arg);
 	TD_SET_CAN_RUN(td);
 
@@ -167,7 +174,7 @@ kproc_suspend(struct proc *p, int timo)
 	}
 	SIGADDSET(p->p_siglist, SIGSTOP);
 	wakeup(p);
-	return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkt", timo);
+	return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo);
 }
 
 int
@@ -194,7 +201,205 @@ kproc_suspend_check(struct proc *p)
 	PROC_LOCK(p);
 	while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
 		wakeup(&p->p_siglist);
-		msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "ktsusp", 0);
+		msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
 	}
 	PROC_UNLOCK(p);
 }
+
+
+/*
+ * Start a kernel thread.  
+ *
+ * This function is used to start "internal" daemons and intended
+ * to be called from SYSINIT().
+ */
+
+void
+kthread_start(udata)
+	const void *udata;
+{
+	const struct kthread_desc	*kp = udata;
+	int error;
+
+	error = kthread_add((void (*)(void *))kp->func, NULL,
+		    NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
+	if (error)
+		panic("kthread_start: %s: error %d", kp->arg0, error);
+}
+
+/*
+ * Create a kernel thread.  It shares its address space
+ * with proc0 - ie: kernel only.
+ *
+ * func is the function to start.
+ * arg is the parameter to pass to function on first startup.
+ * newtdp is the return value pointing to the thread's struct thread.
+ *  ** XXX fix this --> flags are flags to fork1 (in unistd.h) 
+ *  ** XXX are any used?
+ * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
+ */
+int
+kthread_add(void (*func)(void *), void *arg, struct proc *p,
+    struct thread **newtdp, int flags, int pages, const char *fmt, ...)
+{
+	va_list ap;
+	struct thread *newtd, *oldtd;
+	int error;
+
+	if (!proc0.p_stats)
+		panic("kthread_add called too soon");
+
+	error = 0;
+	if (p == NULL) {
+		p = &proc0;
+		oldtd = &thread0;
+	} else {
+		oldtd = FIRST_THREAD_IN_PROC(p);
+	}
+
+	/* Initialize our td  */
+	newtd = thread_alloc();
+	if (newtd == NULL)
+		return (ENOMEM);
+
+	bzero(&newtd->td_startzero,
+	    __rangeof(struct thread, td_startzero, td_endzero));
+/* XXX check if we should zero. */
+	bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
+	    __rangeof(struct thread, td_startcopy, td_endcopy));
+
+	/* set up arg0 for 'ps', et al */
+	va_start(ap, fmt);
+	vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap);
+	va_end(ap);
+
+	newtd->td_proc = p;  /* needed for cpu_set_upcall */
+
+	/* XXX optimise this probably? */
+	/* On x86 (and probably the others too) it is way too full of junk */
+	/* Needs a better name */
+	cpu_set_upcall(newtd, oldtd);
+	/* put the designated function(arg) as the resume context */
+	cpu_set_fork_handler(newtd, func, arg);
+
+	newtd->td_pflags |= TDP_KTHREAD;
+	newtd->td_ucred = crhold(p->p_ucred);
+	/* Allocate and switch to an alternate kstack if specified. */
+	if (pages != 0)
+		vm_thread_new_altkstack(newtd, pages);
+
+	/* this code almost the same as create_thread() in kern_thr.c */
+	PROC_LOCK(p);
+	p->p_flag |= P_HADTHREADS;
+	newtd->td_sigmask = oldtd->td_sigmask; /* XXX dubious */
+	PROC_SLOCK(p);
+	thread_link(newtd, p);
+	thread_lock(oldtd);
+	/* let the scheduler know about these things. */
+	sched_fork_thread(oldtd, newtd);
+	TD_SET_CAN_RUN(newtd);
+	thread_unlock(oldtd);
+	PROC_SUNLOCK(p);
+	PROC_UNLOCK(p);
+
+
+	/* Delay putting it on the run queue until now. */
+	if (!(flags & RFSTOPPED)) {
+		thread_lock(newtd);
+		sched_add(newtd, SRQ_BORING); 
+		thread_unlock(newtd);
+	}
+	if (newtdp)
+		*newtdp = newtd;
+	return 0;
+}
+
+void
+kthread_exit(int ecode)
+{
+	thread_exit();
+}
+
+/*
+ * Advise a kernel process to suspend (or resume) in its main loop.
+ * Participation is voluntary.
+ */
+int
+kthread_suspend(struct thread *td, int timo)
+{
+	if ((td->td_pflags & TDP_KTHREAD) == 0) {
+		return (EINVAL);
+	}
+	thread_lock(td);
+	td->td_flags |= TDF_KTH_SUSP;
+	thread_unlock(td);
+	/*
+	 * If it's stopped for some other reason,
+	 * kick it to notice our request 
+	 * or we'll end up timing out
+	 */
+	wakeup(td); /* traditional  place for kernel threads to sleep on */ /* XXX ?? */
+	return (tsleep(&td->td_flags, PPAUSE | PDROP, "suspkt", timo));
+}
+
+/*
+ * let the kthread it can keep going again.
+ */
+int
+kthread_resume(struct thread *td)
+{
+	if ((td->td_pflags & TDP_KTHREAD) == 0) {
+		return (EINVAL);
+	}
+	thread_lock(td);
+	td->td_flags &= ~TDF_KTH_SUSP;
+	thread_unlock(td);
+	wakeup(&td->td_name);
+	return (0);
+}
+
+/*
+ * Used by the thread to poll as to whether it should yield/sleep
+ * and notify the caller that is has happened.
+ */
+void
+kthread_suspend_check(struct thread *td)
+{
+	while (td->td_flags & TDF_KTH_SUSP) {
+		/*
+		 * let the caller know we got the message then sleep
+		 */
+		wakeup(&td->td_flags);
+		tsleep(&td->td_name, PPAUSE, "ktsusp", 0);
+	}
+}
+
+int
+kproc_kthread_add(void (*func)(void *), void *arg,
+            struct proc **procptr, struct thread **tdptr,
+            int flags, int pages, char * procname, const char *fmt, ...) 
+{
+	int error;
+	va_list ap;
+	char buf[100];
+	struct thread *td;
+
+	if (*procptr == 0) {
+		error = kproc_create(func, arg,
+		    	procptr, flags, pages, "%s", procname);
+		if (error)
+			return (error);
+		td = FIRST_THREAD_IN_PROC(*procptr);
+		*tdptr = td;
+		va_start(ap, fmt);
+		vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
+		va_end(ap);
+		return (0); 
+	}
+	va_start(ap, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, ap);
+	va_end(ap);
+	error = kthread_add(func, arg, *procptr,
+		    tdptr, flags, pages, "%s", buf);
+	return (error);
+}
diff --git a/sys/kern/kern_shutdown.c b/sys/kern/kern_shutdown.c
index 14a74b7f219f..088e781e2335 100644
--- a/sys/kern/kern_shutdown.c
+++ b/sys/kern/kern_shutdown.c
@@ -616,6 +616,28 @@ kproc_shutdown(void *arg, int howto)
 		printf("done\n");
 }
 
+void
+kthread_shutdown(void *arg, int howto)
+{
+	struct thread *td;
+	char procname[MAXCOMLEN + 1];
+	int error;
+
+	if (panicstr)
+		return;
+
+	td = (struct thread *)arg;
+	strlcpy(procname, td->td_name, sizeof(procname));
+	printf("Waiting (max %d seconds) for system thread `%s' to stop...",
+	    kproc_shutdown_wait, procname);
+	error = kthread_suspend(td, kproc_shutdown_wait * hz);
+
+	if (error == EWOULDBLOCK)
+		printf("timed out\n");
+	else
+		printf("done\n");
+}
+
 /* Registration of dumpers */
 int
 set_dumper(struct dumperinfo *di)
diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
index 97c56a4f4595..2a28823015b4 100644
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -657,12 +657,6 @@ thread_single(int mode)
 						sleepq_abort(td2, EINTR);
 					break;
 				case SINGLE_BOUNDARY:
-					if (TD_IS_SUSPENDED(td2) &&
-					    !(td2->td_flags & TDF_BOUNDARY))
-						thread_unsuspend_one(td2);
-					if (TD_ON_SLEEPQ(td2) &&
-					    (td2->td_flags & TDF_SINTR))
-						sleepq_abort(td2, ERESTART);
 					break;
 				default:	
 					if (TD_IS_SUSPENDED(td2)) {
diff --git a/sys/kern/sched_4bsd.c b/sys/kern/sched_4bsd.c
index 50f9aafcab13..058ee0db4453 100644
--- a/sys/kern/sched_4bsd.c
+++ b/sys/kern/sched_4bsd.c
@@ -1367,11 +1367,9 @@ sched_tick(void)
 void
 sched_idletd(void *dummy)
 {
-	struct proc *p;
 	struct thread *td;
 
 	td = curthread;
-	p = td->td_proc;
 	for (;;) {
 		mtx_assert(&Giant, MA_NOTOWNED);
 
diff --git a/sys/sys/kthread.h b/sys/sys/kthread.h
index 3bc83463c0ca..2bd4b33bb36a 100644
--- a/sys/sys/kthread.h
+++ b/sys/sys/kthread.h
@@ -42,13 +42,38 @@ struct kproc_desc {
 	struct proc	**global_procpp;	/* ptr to proc ptr save area */
 };
 
-void	kproc_shutdown(void *, int);
-void	kproc_start(const void *);
+ /* A kernel thread descriptor; used to start "internal" daemons. */
+struct kthread_desc {
+	char		*arg0;			/* arg 0 (for 'ps' listing) */
+	void		(*func)(void);		/* "main" for kernel thread */
+	struct thread	**global_threadpp;	/* ptr to thread ptr save area */
+};
+
 int     kproc_create(void (*)(void *), void *, struct proc **,
 	    int flags, int pages, const char *, ...) __printflike(6, 7);
 void    kproc_exit(int) __dead2;
 int	kproc_resume(struct proc *);
+void	kproc_shutdown(void *, int);
+void	kproc_start(const void *);
 int	kproc_suspend(struct proc *, int);
 void	kproc_suspend_check(struct proc *);
 
+/* create a thread inthe given process. create the process if needed */
+int     kproc_kthread_add(void (*)(void *), void *,
+	    struct proc **,
+	    struct thread **,
+	    int flags, int pages,
+	    char * procname, const char *, ...) __printflike(8, 9);
+
+int     kthread_add(void (*)(void *), void *,
+	    struct proc *, struct thread **,
+	    int flags, int pages, const char *, ...) __printflike(7, 8);
+void    kthread_exit(int) __dead2;
+int	kthread_resume(struct thread *);
+void	kthread_shutdown(void *, int);
+void	kthread_start(const void *);
+int	kthread_suspend(struct thread *, int);
+void	kthread_suspend_check(struct thread *);
+
+
 #endif /* !_SYS_KTHREAD_H_ */
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index c0e91eb7e3b8..6c8bac7d7219 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -322,7 +322,7 @@ do {									\
 #define	TDF_IDLETD	0x00000020 /* This is a per-CPU idle thread. */
 #define	TDF_SELECT	0x00000040 /* Selecting; wakeup/waiting danger. */
 #define	TDF_SLEEPABORT	0x00000080 /* sleepq_abort was called. */
-#define	TDF_UNUSEDx100	0x00000100 /* --available-- */
+#define	TDF_KTH_SUSP	0x00000100 /* kthread is suspended */
 #define	TDF_UBORROWING	0x00000200 /* Thread is borrowing user pri. */
 #define	TDF_BOUNDARY	0x00000400 /* Thread suspended at user boundary */
 #define	TDF_ASTPENDING	0x00000800 /* Thread has some asynchronous events. */
@@ -348,7 +348,7 @@ do {									\
 
 /*
  * "Private" flags kept in td_pflags:
- * These are only accessed by curthread and thus need no locking.
+ * These are only written by curthread and thus need no locking.
  */
 #define	TDP_OLDMASK	0x00000001 /* Need to restore mask after suspend. */
 #define	TDP_INKTR	0x00000002 /* Thread is currently in KTR code. */
@@ -371,6 +371,7 @@ do {									\
 #define	TDP_NORUNNINGBUF 0x00040000 /* Ignore runningbufspace check */
 #define	TDP_WAKEUP	0x00080000 /* Don't sleep in umtx cond_wait */
 #define	TDP_INBDFLUSH	0x00100000 /* Already in BO_BDFLUSH, do not recurse */
+#define	TDP_KTHREAD	0x00200000 /* This is an official kernel thread */
 
 /*
  * Reasons that the current thread can not be run yet.